Has anyone here made a kill box for gassing feeders? I need to do something, I'm producing a lot of extras, and I have people that want them. So I usually trade feed or bedding for my surplus rodents. I just need a humane way to put them down. I'm open to any and all suggestions.

I haven't been there in a while but the "feeders" subforum on KS.com used to have plenty of very specific info on this topic.

I don't know that CO2 is a "humane" way to kill rodents (it's a terrifying and painful death, I think I've heard somewhere), and/but I'm first-hand familiar with your situation. Cervical dislocation or other ACUC-type "approved methods" aren't very practical for larger numbers that need to stay food-grade.

Somebody needs to invent a cattle-style squeeze chute for rodents, in several sizes. I'm not really kidding. Maybe something snugly tubular, with some kind of target (chew? odor? small hole?) to get them to orient their head properly for a sec.

Just another upside to venomous, ha ha. Live prey is so much easier to deal with, both ethically and practically - let the snake handle it.

CO2 is an accepted method. I have a "Killbox" and that is what I actually refer to it as...

Here is an instructional video (that someone else made):

My killbox is pretty much exactly like the one in the video. I found the container at Walmart and the CO2 canister and "remote" CO2 cord at a local Military Surplus store. The "remote" is somewhat expensive (~$50-75). Be sure that the remote has the on/off nozzle (some are just an extension cord).

I used to just give them a quick thump on a hard surface. A little tedious I guess if we're talking volume, but quick (for the rodent). I worked at a nature center once and had to do a couple hundred one day to store as feeders for our birds of prey. I guess that I always just thought that this was how it was done.....

Live-freezing sounds pretty horrible. I dunno, maybe it isn't. Probably not as bad as CO2 gassing for inducing pain and panic. Just a wild guess, I haven't looked into it, it's more of a feeling or notion. Just being "+/- normally-empathic" or something. I am somewhat regularly subjected to CO2 buildup underwater and know that it takes some presence of mind to stay cool about it.

When I was an early teenager with a number of non-vens I did the thump method. My experience was, once in a while it gets bloody. That kinda sucks, blood is quite messy on clothes, carpet, walls, etc. But you can get through a few pretty fast. I never really felt that great about it all, despite the fact I was fulfilling the ethical responsibility to provide a healthy diet for my captives. I was whacking maybe 50 rodents a week. Didn't take but maybe 15 minutes to do the whole Mauschwitz jobbie.

You can be just as fast, and reliably cleaner, with the cervical dislocation - once I learned that, I quit thumping. Pin the head with a little snake hook or screwdriver laid across the back of the skull, yank the tail straight back, dislocate the cervical vertebrae. That is an "approved humane method". Cheaper and more convenient than CO2 unless you've regularly got significant numbers.

Eh, I just assumed they fall asleep before actually freezing to death. Seems to be the case with most other mammals. People have told me that it causes their brains to rupture or something that causes agony, but honestly, I bred them to feed to my snakes. They were kept healthy when they were alive so they would be a good food source. It really doesn't bug me that they might suffer when I kill them. I've had snakes that only eat live food at first, and I imagine all those mice suffer worse than the ones that I throw in the freezer.

If you're worried about CO2 causing pain/panic, switch to another gas, specifically nitrogen (or Argon, Helium, but nitrogen is cheaper). I've personally breathed in CO2 and its a very strong suffocation feeling. Nitrogen is around 70% of the atmosphere we breath. By changing this to 100 percent in a kill box, you'll effectively kill them without any physiological warning systems going off to alert them of their impending fate. They'll simply pass out and never wake up.

As I understand it, problems occur with using carbon dioxide for euthanasia only if it's used without oxygen present, as then the animals actually suffocate while in an alert state and experience some discomfort associated with that. When carbon dioxide is used with oxygen present, the animals quickly become groggy, lose consciousness and then die while unconscious. (It's best to leave them in the euthanasia chamber for a solid few minutes after they go down to ensure they're actually dead; regaining consciousness while freezing to death would probably be an unpleasant experience.)

Lots and lots of institutions' animal care and use committees recognize carbon dioxide-based euthanasia as humane when done properly.

gbin wrote:As I understand it, problems occur with using carbon dioxide for euthanasia only if it's used without oxygen present, as then the animals actually suffocate while in an alert state and experience some discomfort associated with that. When carbon dioxide is used with oxygen present, the animals quickly become groggy, lose consciousness and then die while unconscious. (It's best to leave them in the euthanasia chamber for a solid few minutes after they go down to ensure they're actually dead; regaining consciousness while freezing to death would probably be an unpleasant experience.)

Lots and lots of institutions' animal care and use committees recognize carbon dioxide-based euthanasia as humane when done properly.

Gerry

^ I agree. Though I have thought about switching to nitrogen. I leave things in the kill box for 10-20 minutes after their last movement. Given small mammals' rapid heart rate (and therefore breathing), a little bit of CO2 will put them to sleep pretty quick and then a little more will kill them fairly fast. There is a little skill involved to make sure it goes smoothly without causing significant panic or suffering.

It is way more humane than freezing though (freezing is no longer an accepted method per IACUC or the American Veterinary Medical Association for herps or small mammals). Drowning used to be an accepted method for small mammals but that is being phased out too.

Soopaman wrote:If you're worried about CO2 causing pain/panic, switch to another gas, specifically nitrogen (or Argon, Helium, but nitrogen is cheaper). I've personally breathed in CO2 and its a very strong suffocation feeling. Nitrogen is around 70% of the atmosphere we breath. By changing this to 100 percent in a kill box, you'll effectively kill them without any physiological warning systems going off to alert them of their impending fate. They'll simply pass out and never wake up.

Where does one buy nitrogen? SCUBA store? Can it go into the same sort of tank that is used for CO2?

Ok looks like I'm going to try to out fit a 5 gallon bucket with a tight fitting lid, and get some tubing and a C02 tank from a paint ball shop. I hope that this thread can continue as it seems like there other people with the same concerns as me.

I hope that this thread can continue as it seems like there other people with the same concerns as me.

Yeah, I agree, would love to hear more. Particularly about this:

There is a little skill involved to make sure it goes smoothly

So, um...what does it take? And how do you get "not smoothly"? Not asking for details on what that actually looks like, just "how to, and how not to, screw up the operation". Does this involve making sure there's enough oxygen present, or what? How is that done, and how do you know? (I mean, before getting to "not smooth", that is.)

Soopaman wrote:If you're worried about CO2 causing pain/panic, switch to another gas, specifically nitrogen (or Argon, Helium, but nitrogen is cheaper). I've personally breathed in CO2 and its a very strong suffocation feeling. Nitrogen is around 70% of the atmosphere we breath. By changing this to 100 percent in a kill box, you'll effectively kill them without any physiological warning systems going off to alert them of their impending fate. They'll simply pass out and never wake up.

Where does one buy nitrogen? SCUBA store? Can it go into the same sort of tank that is used for CO2?

-Chris

I'm fairly sure we get ours (for organic synthesis lab) from Sigma Aldrich.
It looks like they ship it with the tank (as opposed to sending a truck with a larger tank, and refilling ours on site), but I can't imagine that you can get those tanks and the gas for $204, unless we're exchanging an old tank every time we get another shipped.

Though really, a tank like this would be something you'd use for a larger operation, or really long term.

Recalling from when I was younger, I had a paintball gun that had a special nitrogen tank that had to be filled with nitrogen gas, and it was only one or two liters. I'm sure you could get one of those, and go to a local paintball field that had nitrogen in a tank like I linked above and get it refilled as needed.

I used to buy nitrogen gas (for another purpose entirely) from an industrial/medical gas supplier in large tanks that weren't really suitable for home use, but apparently it can also be bought in hobbyist-friendly small cartridges just as can carbon dioxide, e.g. on Amazon.

It would be a courteous gesture perhaps to include some stress softening factor to the box - something im sure is not included by large companies, it could be as simple as some dark tubes or handful of straw or hay. It is a pleasant creative challenge to reduce fear in animal care where ever possible and for a few extra moments in our private practices of what has been shown in this forum to be a gentlemens hobby.

I have noticed in discussions about herps,dogs,rats, animals of all kinds you are a gentleman. blunt class.

I was under the impression that if done slowly, CO2 actually causes a euphoric feeling before becoming unconscious. I watched a show once about lake turnover at Lake Nyos http://en.wikipedia.org/wiki/Lake_Nyos. One of the ways the scientists figured out what happened was talking to the survivor(s) that claimed just that.

Yeah, I'm no expert on this stuff, myself, but speaking based on my understanding of the expertise of others: It's not really anywhere near as tricky as trying to get the amount of oxygen or the oxygen:carbon dioxide ratio just right, it's more a matter of simply not trying to replace the available oxygen with carbon dioxide. So I'd think an at least somewhat gradual introduction of carbon dioxide to whatever chamber would do it; if you see signs of excited agitation (as opposed to groggy confusion), you're rushing the process.

The University I graduated from, and (still) get frozen rats/mice from uses CO2 for euthanasia, and it passes all ethical standards in place. I used to do it there, as a matter of course... and if done correctly, is humane.

Even taking brain slices from living anesthetized rats is done in a humane fashion... euthanasia is (comparatively speaking) a minor procedure ... unless of course, you're the rat.

gbin wrote:Yeah, I'm no expert on this stuff, myself, but speaking based on my understanding of the expertise of others: It's not really anywhere near as tricky as trying to get the amount of oxygen or the oxygen:carbon dioxide ratio just right, it's more a matter of simply not trying to replace the available oxygen with carbon dioxide. So I'd think an at least somewhat gradual introduction of carbon dioxide to whatever chamber would do it; if you see signs of excited agitation (as opposed to groggy confusion), you're rushing the process.